量化小组委员会报告

Quantification of Federal Spectrum Use October 9, 2014 The following slides are proposed responses to NTIAquestions that have been prepared by the Subcommittee.CSMAC member comments are solicited. Question 1 How may general occupancy measurements be performedto reflect or validate actual federal spectrum use(particularly radars and intermittent operations) in a waythat can support spectrum management decisionsregarding relocation or sharing of spectrum? (See 6/14/13 Executive Memorandum at Sec. 3(c) and NTIA8/19/13 Notice of Inquiry) Question 1 – Draft Response The CSMAC recommends that the NTIA make spectrum measurements.The general occupancy measurement objective should be to determinehow much spectrum could be shared with incumbent systems. Themeasurements would approximately determine the number oftransmitters, locations, number of channels used, modes typically in use,time-of-day use, etc. However, the measurement process needs torecognize and indicate where there are receive only uses, and other lowduty cycle transmissions that would not be adequately reflected in themeasurement results, e.g., where there are receive only radars, or missiledestruct signals; current analytic techniques are more appropriate for suchsituations as measurements would be potentially misleading. Question 1 – Draft Response The general occupancy measurements should be made incrementallyto support different phases of the spectrum management decision-making process. The duration and the geographic scope of themeasurements should increase if the process for a given set offrequencies moves forward. The purpose/triggers for measurement activity are: Level 0Prior to making any determination to undertake any occupancy measurements, NTIA should analyze the various federal uses andspecific service characteristics (e.g., radar, earth observationsystems, deep space exploration) in bands of potential interest, todetermine if those bands could serve as potential candidates fornext level measurement activity.4 Question 1 – Draft Response Level 1 To inform the process of identifying and prioritizing bands forpotential relocation or sharing. These measurements would beconducted for a period of time and in places, appropriate for theincumbent operations in the band. Level 2 For targeted bands, to determine the scope and technical feasibilityof transitional or long-term sharing.Level 3 For bands identified for relocation or sharing, to informcommercial users (auction bidders). These measurements wouldbe made in all high priority Protection Zones at multiple locations(5 to 10) over long periods (3 to 6 months) to provide acomprehensive and detailed estimate of the existing transmitter’sspatial and temporal characteristics.5 Question 1 – Draft Response The NTIA should develop a multi-tier approach to release share thedata that accommodates security concerns. The detailedmeasurement data should be released to a limited group that areactively considering providing service in the specific areas. NTIAshould investigate data processing methods to obscure criticalmeasurement features (i.e. waveform type, specific frequencies,etc) and maintaining received power level, approximate locationand time of day to enable public releasable data.For example, theamplitude probability distribution of received power in 4 hoursblocks over frequency range blocks could be provided, along withannotation that the source was an airborne transmitter, whichwould provide significant information for spectrum sharinganalysis, but would reveal much less about the DoD systems. Question 1 – Draft Response The NTIA should analyze the measurement data toextrapolate the usage in the future, which can informwhether there is a potential for sharing or relocation.However, measurement characteristics alone are notsufficient to determine future usage, but the spectrumneeds of existing authorized, but not yet deployed,programs need also be reflected in future usage analysis, aswell as any planned growth in current systems. Question 2 Recognizing resource limitations and the lack of real-timereporting of use built within the federal radioinfrastructure, how should actual federal spectrum use bequantified with or without supplemental occupancymeasurements? (See 6/14/13 PM Sec. 3(a) and (d)) Question 2 – Draft Response The CSMAC recommends that the NTIA use spectrum measurementsto selectively validate analytic spectrum interference predictionmodels. These interference models effectively describe federalspectrum use because the prediction models are a fundamental toolused to limit entrant spectrum use. Measurements are critical tointerference models because the models have many assumptions onpropagation models, clutter levels, transmit power levels, transmitterlocations, transmission statistics, and other parameters. Themeasurements should determine the incumbent and/or entrantreceived power level distribution functions at specific locations. Bydirectly comparing t